Additively manufactured (AM) biodegradable zinc alloys hold huge potential as promising candidates for bone defect and fracture repair, thanks to their suitable biodegradation rates and acceptable biocompatibility. However, the mechanical properties of AM zinc alloys developed so far, ductility in particular, fall short of the requirements for bone substitution. Here, we present Zn-1Mn and Zn-1Mn-0.4Mg alloy implants with unique microstructures, fabricated using laser powder bed fusion (LPBF). Notably, the LPBF Zn-Mn-Mg alloy exhibited an extraordinary balance of strength and ductility, with an ultimate tensile strength of 289 MPa, yield strength of 213.5 MPa, and elongation over 20 %, outperforming all previously reported AM zinc alloys. The simultaneously enhanced strength and ductility of the ternary alloy were attributed to the strong grain-refining effect of the Mg₂Zn₁₁ second phase and the synthetic strengthening caused by the dispersion of the MnZn₁₃ and Mg₂Zn₁₁ second phases inside the grains and at the grain boundaries. In addition, both alloys had similar rates of in vitro biodegradation (∼0.15 mm/year), properly aligned with the bone remodeling process, while also demonstrating favorable biocompatibility and upregulating multiple osteogenic markers. The Zn-Mn-Mg alloy showed even better osteogenic potential than the Zn-Mn alloy, owing to the addition of Mg. The combined attributes of the LPBF Zn-Mn-Mg ternary alloy indicated huge potential for its use as a bone repair material, especially for load-bearing bone fixation. Statement of significance: The mechanical properties of previously developed additively manufactured biodegradable zinc alloys, especially ductility, have not met the requirements for bone repair. Using laser powder bed fusion (LPBF), we fabricated Zn-1Mn and Zn-1Mn-0.4Mg alloy implants with unique microstructures. The LPBF Zn-Mn-Mg alloy demonstrated an exceptional balance of strength and ductility, achieving a tensile strength of 289 MPa, yield strength of 213.5 MPa, and elongation over 20 %, surpassing all reported AM zinc alloys. This study is the first to produce a directly printed biodegradable alloy meeting the mechanical requirements for bone fixation devices without post-processing. Additionally, the alloy exhibited moderate a biodegradation rate and excellent biocompatibility, underscoring its potential for load-bearing bone repair applications.

In this work, we introduce SEESys, the first system to provide online pose error estimation for Simultaneous Localization and Mapping (SLAM). Unlike prior offline error estimation approaches, the SEESys framework efficiently collects real-time system features and delivers accurate pose error magnitude estimates with low latency. This enables real-time quality-of-service information for downstream applications. To achieve this goal, we develop a SLAM system run-time status monitor (RTS monitor) that performs feature collection with minimal overhead, along with a multi-modality attention-based Deep SLAM Error Estimator (DeepSEE) for error estimation. We train and evaluate SEESys using both public SLAM benchmarks and a diverse set of synthetic datasets, achieving an RMSE of 0.235 cm of pose error estimation, which is 15.8% lower than the baseline. Additionally, we conduct a case study showcasing SEESys in a real-world scenario, where it is applied to a real-time audio error advisory system for human operators of a SLAM-enabled device. The results demonstrate that SEESys provides error estimates with an average end-to-end latency of 37.3 ms, and the audio error advisory reduces pose tracking error by 25%.

With the development of unmanned vehicle technology, unmanned vehicles have played a huge role in logistics transportation, emergency rescue and disaster relief, etc., so the research on unmanned vehicles is becoming more and more important. Road detection is an important part of environmental perception and an important factor in the realization of assisted driving and unmanned driving technology. High-precision road detection technology can provide important environmental information for efficient planning and reasonable decision-making of unmanned vehicles. Firstly, the technical framework of road detection is given, and the road detection process is introduced in detail. Then, the vision-based road detection algorithm is introduced. Finally, some related data sets in the field of road detection are collected, which provides new ideas and methods for road detection researchers.

The coupled vehicle-track system (CVTS) dynamics have been extensively investigated for decades. However, the calculation accuracy of prevailing vehicle-track coupling models needs to be improved in the high frequency range due to the inappropriate model simplification and neglect of material nonlinearity. In this study, we propose a refined numerical model of the CVTS that considers the nonlinear properties of the railpads and primary suspension using the fraction derivative Zener model. Furthermore, we more realistically simulate the wheelset, rail and railpad configuration with the elastic axle, solid finite element and surface-support models, respectively, and improve the computation efficiency by employing the mode superposition method. The results demonstrate that the refined CVTS model is more accurate than the classical model in simulating vehicle-track coupling dynamics above 2 kHz. In particular, there are significant differences in the dynamic response of the elastic wheelset model compared to the rigid model over a broad frequency range, with an 11% difference in the bogie acceleration response at the first dominant frequency. When the railpads are modeled using the surface-support model, the rail acceleration differences exceed 41% near 1 kHz and 44% near 2650 Hz, compared to the point-support model. Additionally, the rail response at various locations across the rail cross section can be calculated using the finite element method in this refined model. Overall. the proposed CVTS model provides high accuracy and efficiency for random vibration analysis, especially in the high frequency domain.